The US Senate voted on Friday to confirm Representative Tom Price as the top US healthcare official, putting a determined opponent of Obamacare in position to help President Donald Trump dismantle the healthcare law.

The Senate voted 52-47 to approve the conservative Georgia Republican and orthopedic surgeon as secretary of the Department of Health and Human Services (HHS), a massive department with an annual budget of more than $1 trillion.

His confirmation opens the door for lawmakers to consider Trump's US Treasury secretary designate, Steven Mnuchin. A vote on his nomination is expected on Monday.

Price, in his new job, will have authority to rewrite rules implementing the 2010 Affordable Care Act, also known as Obamacare. Price could move quickly to rework the law's regulations while waiting for Republicans in Congress to keep their pledge to scrap the law entirely.

Republicans, who have the majority in Congress, are trying to craft a replacement for Obamacare but have not agreed on one. Twenty million Americans gained health insurance under the law.

"Having Dr. Tom Price at the helm of HHS gives us a committed ally in our work to repeal and replace Obamacare," said US House Speaker Paul Ryan, who has vowed to pass a new plan this year.

Trump signed an order on his first day in office directing government agencies to freeze Obamacare regulations and take other steps to weaken the law, a directive that will fall largely on Price. Trump, in a Fox News interview this month, said a replacement may not come until next year.

Price's nomination was dogged by questions about his trading in hundreds of thousands of dollars in health company stocks while working on healthcare legislation. Democrats boycotted the committee vote on his nomination, saying he had made misleading statements. Price has said his actions were legal and ethical.

A member of the House of Representatives since 2005 who chaired the budget committee, Price wrote legislation to repeal Obamacare and replace it with age-adjusted tax credits for the purchase of health insurance.

Democrats criticized Price for his stock trading as well as his opposition to Obamacare, his ideas about restructuring the Medicare program for the elderly, and his support for cutting federal funds to Planned Parenthood, an organization that provides abortions and other affordable healthcare and education services.

HHS oversees Medicare and Medicaid, the government health insurance programs for the elderly, disabled and poor. It also encompasses the Centers for Disease Control and Prevention and the Food and Drug Administration.